Fix OS detection for OpenSolaris

This fixes the OS detection for OpenSolaris, allowing it to be properly
recognized and for 'os' and 'osrelease' grains to be set correctly.
Fix regex

My previous commit broke Solaris detection while fixing OpenSolaris.
This fixes that.
Merge pull request #10601 from terminalmage/opensolaris-os-detection

Fix OS detection for OpenSolaris